Valve.



VALVE. APPLICATION IFILEUKNOV. 21. 1915.

1,185,516. Patented May 30,1916.

3fm/nemica F. MACVIC/IR` VALVE.

APPLICATION FILED NOV. 27. I9l` Patented May 30,1916.

2 SHEETS-SHEET 2.

riiANK MACVICAE, or sYEAcUsE, NEW YORK.

VALVE.

Specification of Letters Patent.

Patented May 30, 1916.

Application mea November 27, 1915.v serial No.

vsprings fail to cause the tappets to iemain in engagement with the camwhen the latter travels at a high rate of speed, thereby materiallydecreasing the efficiency of the motor, and necessitating the cam tooperate against both the resistance of the spring and the pressure ofthe valve, thus subjecting the cam or cams to-undue wear.

It is the primary object of my invention to eliminate these objections,by providing a cam controlled valve mechanism, embodying a yieldablemeans for holdingr the tappets in continuous engagement with the openingand closing cams respectively, the closing cam possessing a greaterthrow than -the opening cam with a view of tensioning said yieldablemeans for the purpose nientioned.

Another object of importance resides in the provision of the abovementioned mecha. nism, wherein said yieldable means serves to cushionthe eitra throw of the closing cam,

'thereby eliminating bottoming as the valve engages its seat.

In carrying out my invention I aim to provide a cam controlled valvemechanism, which will materially lessen the wear upon the cams andnecessitate the use of less power to operate said valves.

The nature and advantages of the invention will be thoroughly understoodwhen the following description Ais taken in connection with theaccompanying drawings, the invention residing in the construction,combination and arrangement of parts as claimed.

In the drawings forming part of this speciicationlike numerals ofreference indicate similar parts throughout the .several lviews andwherein:-

Figure 1 is an elevation of the preferred form of the invention 'showingthe normal position of parts when thevalve is closed. Fig: 2 is asimilar view showing the active position of the parts when the vvalve isopened. Fig. 3 is a perspective view of the cam. Fig. 4 is an elevationof a modified form ofthe invention showing the valve closed. Fig. 5 is asimilar view showing the valve opened.

Referring to the drawings in detail, 5 indi-- Cates the enginecylinder'having the usual seat 6 and the inwardly opening valvel?, thestem 8.of the latter being slidably mounted within the guide'Q andadapted to be operated in the mannerv to be presently described. Asshown in Figs. land 2 I make use of a pair of spaced superimposed rockerarms 10 and 11 respectively, which arms are fulcrumed at a pointapproximately midway of their length as at 12. The rocker arm 10 isoperatively associated in any suitable manner with the upper end of thevalve stem 8 while the lowermost rocker 11 has its forward end providedwith an opening 13 through which thestein is adapted toslide. Theopposite end of each rocker carries a roller 14 and 15 respectively, thelatter normally engaging'th'e cam 16 while the roller 15 normallycontacts the cam 17, which cams are arranged upon the shaft A18.Encircling the stem 8 is a coil spring 21 disposed between the rockerarms 10 and 11 respectively. "The spring has one end seated upon theforward end of the rocker arm 11 while the opposite Yend of the springengages a nut 22 adjustably mounted upon the valve stem 8 at its upperend, and by means of which the tension of the spring can be readily andeasily regulated. In the position of parts as shown in Fig. 1, thespring is compressed and under tension, for the expressed purpose ofmaintaining the rollers 14 and 15 in continuous engagement with theirrespective cams, irrespective of vthe speed at which these cams maytravel. The cam 1G is of usual construction, and when the actuatingsurface 19 thereof engages the roller 14, the rocker arm 10 is movedupon its fulcrum depressing the valve stem 8 and moving the valve toopened position as clearly illustrated in Fig. .2'. In this position ofparts the roller 15 is received within the depressed or dislied portion.20 of the cam 17, which portion is arrangeddiametrically opposite theactuating surface 19 of the cam 16 and which arrangement permits of" theexpansion of the' spring 2l.

o the casing 34 is closed bymeansA of a nut It is of course to beunderstood thatas the actuating surface 19 of the cam 16 is moved out ofengagement with the roller 14, the

,cam 16 is also being rotated to bring its highest portion of thedepression 20 into active engagement with theroller 15, at which timethe stem 8 is moved in a reverse direction for the purpose of seatingthe valve 7. It is manifest from the relative dimensions and formationsof the respective cams 16 and v17, that the closing cam 17 has a greaterthrow than that possessedby the opening cam 16, by reason of which factthe spring 21 is not 1n any way affected by the operation of the cam 17in the clos-` ing ofthe valve.' However subsequent to the seating of thevalve 7, the spring 21 serving as a cushioning means to take care. ofthe extra throw of the closing cam 17, is compressed and movement equalto the dierence between the throws of the respective cams,

during which operation of the spring, the latter is again placed` undertension in the position of parts shown in Fig. 1, for the -position inthe cylinders.

are constructed and arranged upon the shaft` 25 in identically the samemanner as the cams 16 and 17 respectively as hereinabove described.However the tappet as shown in this form of the invention preferablyconsists of a rectangular frame 26 within which the shaft 25 and thecams are arranged to operate. It might herel be stated that -thisembodiment of the invention may be arranged immediately above the valvein the manner illustrated or it can be used by placing the cam shaft inthe base of the motor and also where the valves are in horizontal A Theupper and lower members 27 and 28 of the frame arel provided withsemicircular projections 29 u and 30 respectively, the closing cam 24operating upon the projection 29 around its entire circumference, whilethev actuating surface 21 of the openingvcam 23 operates upon theprojection 30. The lower member 28`has depending centrally therefrom anextension 32 slidably fitted within a suitable guide 33 and carries atits free end a relatively large casing 34. The lower end of 35 which isadjustably associated with the casing, and slidably passed through thecentral opening in the nut is a vvalve stem 36 6.5 ,of the valve 37.-The upper endfof the valve stem is normally spaced a slight distancefrom the adjacent end of the casing 34, which distance .is equal to thedifference of throw between the opening and closing cams respectively,the purpose of which will be presently described. Arranged within thecasing 35 and encircling the stem 36 is a coil spring 39 having one endseatedy upon the nut 35 and its opposite end engaging a nut 38adjustably mounted upon the upper end of the stem 36 for the purpose ofregulating the tension of the spring. j Y

N ow las the shaft 25,is rotated and the actuating surface 31 of the cam23. brought into engagement with the projection 30, the tappet includingthe frame 26, extension 32, and casing 34 is moved against the valvestem 36, therebymoving the ,valve 37 away from its seat, Aas 'showninFig. 5. vIn the normal or closed position of the valve as shown inFig.4the spring 39 is compressed and under t4a'nsi`on,`.y but when thevalve is moved to opened position as shown in Fig. 5 this springispe'r'mitted to expand, thereby moving the valve 4 stem 36 intoengagement with the upper end of the casing 34. As the shaft 35 isrotated to. move the actuating surface 31 of the cam 23 out ofengagement with/the projection 30, the caml 24 is simultaneously'rotated'to bring the highest portioriof the? depleion 40 thereof intoengagement with the projection 29 thereby moving the tappet in itsentirety in a direction 'opposite that-in `which it was moved by the cam23 for the purpose of seating the valve 37. The relative dimens4 f sionsand formations of the respective cams,

attributes to,. the closing cam 24 a slightly` greater throw@ than thatpossessed by the opening cam 23, and subsequent to the'closing ofthevalve 37 by means of the cam 24, the

ter, which not only eliminates considerable wear upon these parts, butrenders the valve to be more easily and properlytimed when the cam shafttravels at a high rate of speed. While I' have shown and describedseveral embodiments of the' invention I desire -to have it understoodthat I do not limit myself to this precise' construction and ar- 1. Thecombination with a cylinder of an ,12.5 rangement of parts, and thatvariouschanges f internal combustion engine, anda valve therefor, ofvalve operating mechanism including opening and closing camsrespectively, a valve actuating device adapted to engage the opening andclosing cams rev for, of valve operating mechanism including opening andclosing` cams respectively, a valve actuating device adapted to engagethe opening and closing cams respectively,

a-syieldable means for vholding said device in continuous engagement'with saidcams, and means for regulating the tension of said yieldablemeans.

`3; The combination with a of aninternal combustion engine, and a-`valve v therefor, of a valve operatingl mechanism including opening andclosing cams respec-l tively, a valve actuating deviceadapted to engagethe opening and closing cams re- 25 spectively, yieldable means normallyunder tensionforholdin said devicein continuous engagement with saidearns, `'one of said ,earns decreasing the tension of said means,

and thevother of said cams placing said means under tension.

- 4. The'combination with a cylinder of an internal combustion engine,and a valve therefor, ofayalve o erating mechanism in# 'cluding openingan 'closing cams respectively, a valve actuating device f adapted to'engage said cams, an extensile spring encircling 4the valvestem andoperating to hold the valve actuating device in continuous enr gagementwith the respective cams and means for regulating the tension o saidspring.

5. The combination with a cylinder of an internal combustion engine, anda valve therefor, of a cam controlled valve mechanismv including atappet operatively associated withv the valve and adapted to engage theopening and closing cams respectively, a. yieldable means operating'tohold said tappet in continuous engagement with said cams, and saidclosing cam having a greater throw than the opening cam for compress#ing and placing said'yieldable means under tension as described. l

6. In combination with a cylinder of an internal combustion engine, andya valve therefor, of a tappet including a pair ofspaced parallelrockingarms, one of said arms being terminally associated with the S'temof the valve, said stem being slidably fitted in the adj-acentend of theother of said' arms, a cam for operating said `arms to open the valve,-asecond cam 'operating to close said valve, a yield' able meansinterposed between said arms operating tov hold the latter in continuousengagementwith their respective cams, and one of said cams having agreater throw --than the other for compressing and placing saidyieldable means under tension.

' In testimon whereof I -affix my signature in presence o two witnesses.

. FRANK MAQVICAR.

Witnesses: l t

CHARLES MACVICAR,

EDITHl M. MACVIGAR.

capite# of'tll patent my be obtainedptpr ive centsY each, by addressingthe Commissioner of Intenta,

washington, D. c."

